Abstract: Bacillus strain compositions and methods for converting (i) one or more polysaccharides into short chain polysaccharides and/or monosaccharides and/or (ii) one or more proteins into short chain polypeptides and/or amino acids are provided. The Bacillus strain composition can comprise Bacillus subtilis 750 or an active variant thereof, and optionally at least one of Bacillus subtilis 747, Bacillus subtilis 839, Bacillus subtilis 1781, Bacillus subtilis 1999, Bacillus subtilis 2018, or an active variant thereof. Compositions provided herein can be fed to animals in an effective amount to increase digestibility of one or more polysaccharides and/or one or more proteins; increase nutrition efficiency and/or energy partitioning; increase nutrient absorption; enhance gut immunity and/or gut barrier integrity; and/or inhibit a pathogen in the gastrointestinal tract of the animal.